Update PS3 controller tutorial for python3

dlech · dlech · commit 190e4ecc8e48 · 2017-01-03T21:40:31.000-06:00
Fixed up the sample code for python3. Also fixed inconsitent capitalization of words and a few other minor things. Fixes ev3dev#321
diff --git a/docs/tutorials/using-ps3-sixaxis.md b/docs/tutorials/using-ps3-sixaxis.md
@@ -8,44 +8,45 @@ author: "@antonvh"
 {:toc}
 
 The cool thing about the PS3 gamepad is that it's a normal Bluetooth device and
-connects directly to the EV3. You can easily run programs in brickman and use
-the pad without another computer or laptop.
+connects directly to the EV3. You can easily run programs in Brickman and use
+the gamepad without another computer or laptop.
 
 # What you need
 - A PS3 gamepad (also known as Sixaxis controller or Dualshock 3)
-- A mini-usb / usb cable
-- A working ssh and internet connection to the Ev3 (or other ev3dev device)
-- ev3-ev3dev-jessie-2015-12-30.img or later
+- A USB mini-B to USB A cable (like the one that comes with the EV3)
+- A working ssh and internet connection to the EV3 (or other ev3dev device)
+- ev3-ev3dev-jessie-2016-12-21.img or later
 
 # Connection
 The PS3 pairing process in Brickman is a little strange, but works fine. Stick
 exactly to these steps: 
 
-1. On the Ev3 brick go to 'Wireless and Networks' > 'Bluetooth'
+1. On the EV3 brick go to 'Wireless and Networks' > 'Bluetooth'
 2. Make sure Bluetooth is Powered and the brick is Visible. 
-3. Connect the gamepad via a mini usb cable to the Ev3. I used the large usb
-    port next to the micro SD slot.
+3. Connect the gamepad via a mini USB cable to the EV3. I used the large USB
+   port next to the microSD slot.
 4. Under Devices a 'PLAYSTATION(R) 3 controller' should show up. But don't pair!
 4. Remove the USB cable again.
 5. Press the PS3 button on the gamepad.
 6. The brick now asks "Authorize service HID?" Press "Accept" 
 
 You're done! Whenever you press the PS3 button on the gamepad now, it will try
-to connect to the ev3 brick. Nice!
+to connect to the EV3 brick. Nice!
 
-If brickman doesn't work or if you don't have a display, like on a BrickPi,
-`bluetoothctl` is the way to go. The gentoo linux guys wrote [a nice tutorial](https://wiki.gentoo.org/wiki/Sony_DualShock)
+If Brickman doesn't work or if you don't have a display, like on a BrickPi,
+`bluetoothctl` is the way to go. The Gentoo Linux guys wrote [a nice tutorial]
+(https://wiki.gentoo.org/wiki/Sony_DualShock)
 
 
 # Running motors with a PS3 sixaxis controller
-Now on to Python. In python we need the evdev (without a 3) to read gamepad
+Now on to Python. In python we need the `evdev` module (without a 3) to read gamepad
 events. Here's a quick program that will take the right stick Y axis and use it
 to set the speed of a motor in port A. Note that motor control is in a separate
 thread. That's because controlling the motors is much slower than reading the
 gamepad. Multithreading synchronizes both.
 
-{% highlight python %}
-#!/usr/bin/env python
+```python
+#!/usr/bin/env python3
 __author__ = 'Anton Vanhoucke'
 
 import evdev
@@ -61,15 +62,15 @@ def scale(val, src, dst):
     src: tuple
     dst: tuple
 
-    example: print scale(99, (0.0, 99.0), (-1.0, +1.0))
+    example: print(scale(99, (0.0, 99.0), (-1.0, +1.0)))
     """
     return (float(val - src[0]) / (src[1] - src[0])) * (dst[1] - dst[0]) + dst[0]
 
 def scale_stick(value):
     return scale(value,(0,255),(-100,100))
 
 ## Initializing ##
-print "Finding ps3 controller..."
+print("Finding ps3 controller...")
 devices = [evdev.InputDevice(fn) for fn in evdev.list_devices()]
 for device in devices:
     if device.name == 'PLAYSTATION(R)3 Controller':
@@ -86,7 +87,7 @@ class MotorThread(threading.Thread):
         threading.Thread.__init__(self)
 
     def run(self):
-        print "Engine running!"
+        print("Engine running!")
         while running:
             self.motor.run_direct(duty_cycle_sp=speed)
 
@@ -103,19 +104,19 @@ for event in gamepad.read_loop():   #this loops infinitely
             speed = scale_stick(event.value)
 
     if event.type == 1 and event.code == 302 and event.value == 1:
-        print "X button is pressed. Stopping."
+        print("X button is pressed. Stopping.")
         running = False
         break
-{% endhighlight %}
+```
 
-Copy this code into a file on the Ev3 brick to run it. If you do
-`sudo chmod +x your_file_name.py`, you can even run it from the brickman interface!
+Copy this code into a file on the EV3 brick to run it. If you do
+`chmod +x your_file_name.py`, you can even run it from the Brickman interface!
 
-# The complete event type and code mapping of the ps3 controller
+# The complete event type and code mapping of the PS3 controller
 I mapped out all codes for you! Here they are:
 {% include /util/screenshot.html source="/images/Website/sixaxis_event_codes.png" %}
 
 # The result: a remote controlled robot
-How cool! No computer needed. Just a gamepad and the ev3 brick. 
+How cool! No computer needed. Just a gamepad and the EV3 brick.
 
 {% include /util/youtube-embed.html youtube_video_id="brfgF3D5c4k" %}
